The band - made up of will.i.am, Fergie, apl.d.ap and Taboo - used to have trouble controlling the 35-year-old rapper, leading to his decision to sober up because he was a "f**king mess".
He exclusively told BANG Showbiz: "I was an embarrassment to the crew. This was during the big-time, yeah man. From 2003 to 2007 when I got arrested, I was a f**king mess. I was always drunk, doing drugs. It didn't matter man."
Taboo - real name Jaime Luis Gomez - was arrested by police for drink driving and drug possession, and he admits his life has never been better thanks to the arrest.
He said: "I almost lost everything and I just thought, 'F**k this man.' Now I'm four years sober and I'm loving life and enjoying the great things that are happening now that I've become clear headed and sober."
However, he believes the band are now closer than ever because they all have respect for each other.
He said: "We're very diplomatic when it comes to our friendship. There's no egos. Everybody is respectful. We don't let fame or even fortune get in the way."